In order to increase transmitted power and to realize quick charging of secondary batteries, inductor units including a plurality of inductors are placed in both the transmitting side (primary side) and the receiving side (secondary side) for non-contact power supply systems. For higher transmission efficiency, the coupling coefficient between the inductors located in the same side needs to be kept low. Also, for the sake of safety to the human body and lower electromagnetic noise, it is necessary to reduce the strength of leakage magnetic field.
If inductors in the same side are located so that they are in a certain angle, it is possible to reduce the coupling coefficient. Also, by configuring the current of each inductor to opposite phases or by winding the coils in the opposite direction, it is possible to reduce the leakage magnetic field. If the inductors belonging to the same side are located adjacently, the attenuation effect of leakage magnetic field becomes stronger. However, due to physical restrictions, it is difficult to reduce the distance between the inductors.